When operating a hydrostatic machine under idle conditions with no external load applied, the pistons of the machine reciprocating in the cylinder bores cause substantial hydraulic losses which decrease the efficiency of the machine.
It is therefore highly desirable to provide a hydrostatic machine of a known type with a clutch for separating the machine from the mechanical drive system to avoid hydraulic losses in running idle and to improve the efficiency.
Prior to the present invention, clutches and/or brakes have been added to axial piston machines. For example, an axial piston machine is provided with a spring-operated multiple-disc brake (design Rexroth) to act on the drive shaft of vehicles and hoisting equipment. Furthermore, a conical friction brake mounted to the drive shaft of an axial piston machine (design Molly) is known to reduce the speed of the machine to zero.